Good tasting versatile cake for stacking/tiers

I have been doing cakes for friends and families for a while but now I want to take this into a business. I have sooo much to learn and so I really appreciate this discussion board.

I watch these cake shows where you see them handle these cakes (before they are frosted etc..) pretty roughly, flipping them around and the cakes hold together well. What is a good versatile recipe that is easy to work with (sturdy and does not have to be baby-ed) that can be changed up in flavors. Is it a sponge cake they are working with? I am always amazed at how they will grab up a layer, flip it onto the board and it never crumbles, falls apart etc... I always feel like I have to handle it with kid gloves or it cracks or falls apart. Know what I mean?

I use a fantastic poundcake recipe that has taken me years to develop(sorry I don't share it) But, I can tell you that it has extra leavening(salt, baking powder) in it to create a very moist, but light cake that is excellent for carving and stacking.